YoloMouse - An open source tool for changing your game cursor.
RealWorld Cursor Editor - Create cursors for Windows, convert images to static or animated cursors, or customize your cursor.
Mousecape - A free cursor manager for Mac OS 10.8+ built using private, nonintrusive CoreGraphics APIs.
CursorFX - Create custom mouse cursors with CursorFX.
AniFX - AniFX is a freeware cursor editor.
Microangelo Toolset - Create Vista icons with Toolset's Icon Editor.